


On The Other Side Of The Other Side

by Nikikeya



Category: Undertale (Video Game), nexustale
Genre: Alternate Universe, Cinnamon Roll Sans (Undertale), F/F, Human/monster relationship, M/M, cuteness, messing with canon, playing in Mercy_Run's sandbox a bit
Language: English
Status: In-Progress
Published: 2020-08-23
Updated: 2020-08-23
Packaged: 2021-03-06 15:35:47
Rating: Not Rated
Warnings: No Archive Warnings Apply
Chapters: 2
Words: 3,701
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/26061283
Author URL: https://archiveofourown.org/users/Nikikeya/pseuds/Nikikeya
Summary: Undertale Sans is stuck in Nexustale with the counterparts of his brother, Alphys, and Undyne. Convalescing and learning about the surface, and getting to know Papyrus better.Just a series of lil drabbles set in Nexustale universe, as that has always been my favorite part of Mercy_Run's fic.
Relationships: Alphys/Undyne (Nexustale), Papyrus/Papyrus/Sans, Papyrus/Sans (Undertale)
Comments: 3
Kudos: 9





	1. CHAPTER 1: VINEGAR

**Author's Note:**

  * For [Mercy_Run](https://archiveofourown.org/users/Mercy_Run/gifts).
  * Inspired by [On the Other Side](https://archiveofourown.org/works/6255382) by [Mercy_Run](https://archiveofourown.org/users/Mercy_Run/pseuds/Mercy_Run). 



> So a few eons ago I promised [Mercy_Run](https://archiveofourown.org/users/Mercy_Run/pseuds/Mercy_Run) I would write 600 passionate words about they're wonderful Papyrus/Sans fic [On the Other Side](https://archiveofourown.org/works/6255382/chapters/14333242)
> 
> An attempt is being made. 2 chaps so far, more to come hopefully if my brain will cooperate.

** CHAPTER 1: VINEGAR **

_**Papyrus learns something that he would rather have not known.** _

During the few days they had known the monster, both Papyrus, and Alphys had come to realize that Sans had had very little to no exposure to fine cuisine... or most foods really.... The Skeleton knew about: hamburgers, fries, hotdogs (Which he called "Hotcats"), spaghetti, pie, cinnamon buns (which he mispronounced adorably as cinnamon "bunnies". ((Alphys was having an increasingly hard time keeping herself from cooing over the little skeleton.)) Quiche, stake, fried snowballs??? Dog food (which Papyrus had been quick to inform him that they would not be serving here, as humans most assuredly did not eat dog food.) and sandwiches. All of which were decidedly on the lower side of the culinary scale.

The two humans had thus made it their sacred mission to try and expose Sans to as many new foods, and drinks as they possibly could. This had lead to them spending time bent over Undyne's laptop searching for recipes, and then scouring the house for the needed ingredients.

Sans spent the majority of this time in on the sofa, either napping or flipping through the seemingly endless array of channels on the tv. The small skeleton had been amazed at the sheer number of different shows on. And upon questioning had revealed that in the Underground there had only been one channel, MTT TV run by a robot monster named Mettaton.

Sans had fallen in love with the educational channels, and had spent an hour (much to Alphys and Papyrus' amusement.) Watching a documentary about Pandas on the Animal Channel.

But when he'd found the channel devoted to Aeronautics and Space Science, both former scientists could plainly see that they had lost him.

And so it was that while Alphys and Papyrus worked to cobble together something for dinner. Sans sat on the sofa with starry eyelights watching a very long winded documentary about Super Novas. Soaking in every word like a sponge, as dazzling pictures of space danced across the screen.

By the time that dinner was ready Papyrus had had to pick Sans up and carry him away from the tv.

He spent the majority of dinner that night (after the initial flurry of questions about the dish (stuffed cabbage rolls baked in tomato sauce.) Telling Alphys and Papyrus all about the shows he had watched between bites of food and appreciative noises.

Papyrus hadn't seen the tiny monster stop smiling once the entire evening. And after dinner the three had retired to the living room and watched a bunch of space themed Anime.

Sans was amazingly giggly during the shows, something that at first had made Papyrus very happy, but had soon tipped him off to something being slightly... wrong...

Sans had become increasingly "punny" during the course of the evening, and letting out an at first seemingly unending torrent of worse than usual puns, that had thankfully tapered off eventually. Papyrus looked down however when small arms suddenly wrapped themselves around his forearm, and a small warm skull nuzzled his bicep.

Sans sat there, his whole skull glowing cyan, as he giggled, and nuzzled Papyrus' arm.

"That" was not normal behavior, and Papyrus had immediately become worried about the tiny skeleton.

"Sans... what are you doing?" Papyrus asked carefully.

The little monster giggled harder.

"nothin... wadda yer doin..?" he mumbled, voice slightly slurred.

Papyrus' sucked in a breath sharply, the sound of which seemed impossibly loud in the now silent room. Alphys having paused the show.

"Sans how are you feeling right now?" Papyrus asked gently.

Sans giggled and squirmed happily, "good... yer really soft pap. soft, soft, silky soft.~" he sang, nuzzling harder than before.

Papyrus looked up at Alphys, who seemed to be torn between being horrified, and giggling her butt off, as the realization hit both of them that somehow, someway, the teeny, tiny, giggly, little skeleton sitting between them was DRUNK.

The accusations didn't take long to start flying.

"Alphys!! What did you put in those cabbage rolls!!?" Papyrus demanded, grabbing the tiny skeleton up in a protective embrace.

"No-nothing I- I f-f-followed the recipe p-perfectly I swear!!!" The shorter human cried, tearing up.

"That's impossible! He is clearly intoxicated. You must have added something! Unless you expect me to believe that the vinegar did it!" Papyrus sputtered angrily.

"W-well vinegar is fermented just like wine, maybe it's more potent for Skeletons. I-I mean t-think about it; they don't have livers or kidneys to p-process it."

Papyrus and Alphys both stopped and looked down at the little skeleton squirming in Papyrus' lap, beating his tiny fists against the man's chest sluggishly.

"papy lemme gooo.~" Sans whined small body going limp in his arms. Sans hung there, arms fidgeting.

"Doesn't..." Alphys begin nervousness tinged with a growing amusement, "Isn't Ketchup made with vinegar?"

Papyrus stared between her and the drunken monster in his arms. And then gave a long, drawn-out groan.

"Oh my God, my boyfriend is an alcoholic!"

"And you've been supplying his habit." Alphys snickered.

Papyrus refused to look at either of them for the rest of the night...


	2. CHAPTER 2: Among the Trees

**Summary for the Chapter:**

> Papyrus and Sans take a walk through the woods.

** CHAPTER 2: Among the Trees **

Sans soul buzzed gently, as he sat securely cradled against the human version of his brother's chest, feeling a steady beat below his fingers.

"That's my heartbeat."☆ Papyrus had answered, amusement shining in his blue eyes upon noticing the tiny skeleton's confusion at the soft fluttering sensation emanating from his chest.

"heartbeat..?" Sans murmured curiously, laying one small hand over the right side of Papyrus' chest.

"The heart is the organ responsible for pumping blood around the body." The man explained calmly, "bloods what keeps everything going, it delivers oxygen and sugars to the organs... ah... you probably already know that though..." he trailed off lamely, blushing.

Sans smiled up at him shyly, "the practical applications yeah... still, readin' bout it in a book and experiencing it first hand's two entirely different things... skeletons don't have hearts...don't have the guts for it."

He peeked up, and Papyrus made a show of taking a deep breath to try and keep from screeching.

It had the desired effect, and the little skeleton squirmed happily, trying very hard to contain his gleeful giggles.

Papyrus beamed at the adorable action, and lowered his head to press a kiss to the tiny skull. Immediately a dusting of cyan flared up. And Sans hide his face in the red scarf flusteredly, little hands fisting into the fabric of Papyrus' jacket. Papyrus just smiled even wider, all his teeth on full display and chuckled as he rubbed Sans small back.

They moved in under the shade of the trees, and Sans finally looked up at the faint sounds of rustling overhead. Eyes wide, he stared up at the leaves watching as they shifted and swayed in the breeze.

Papyrus just stood and watched the look of innocent delight on the tiny skeleton's face.

"Didn't you say that they had trees Underground?" he asked finally, unable to contain his own curiosity any longer.

"mn."Sans hummed, large opalescent eyelights never leaving the dancing leaves above, "hundreds and hundreds of gyftmas trees..."

"GIFTmas trees?" Papyrus asked, perplexed.

"big angular trees with fuzzy branches filled with thousands of little dark green needles..." Sans murmured distractedly.

Everything finally clicked for Papyrus. Giftmas trees. CHRISTMAS TREES. Fir trees...

"Coniferous trees... of course... you said that it was always snowing there, so it makes sense... So you've never seen Deciduous trees before?"

"deciduous?" Sans asked.

"Trees like these that loose there leaves in the Winter months." Papyrus explained, "During the Summer the leaves are green, then, come Autumn, as the days grow shorter, and it gets colder, the trees stop photosynthesizing, and the Chlorophyll that makes the leaves green starts to break down and as it does the leaves change color, to gold, or fiery orange, or vibrant red-"

"they turn red?" Sans asked, looking from the leaves, down to the bright red scarf around Papyrus' neck.

Papyrus smiled gently, not even minding the interruption, "Yup. Just like that... eventually all the leaves fall off the trees onto the ground, and the branches will stay bare all through the Winter until next Spring when little buds will form and eventually unfurl into new green leaves, that will grow throughout the Spring and Summer and then repeat the process again come Autumn..."

Sans sat mesmerized by the leaves. Papyrus in turn just stood there once more, watching as light and shadow played across Sans' small pearly white skull.

Sans finally turned to look back up at the human and gave another shy smile.

"i really like these kinds of trees. they're way prettier than the trees back home. gyftmas lights or no."

Papyrus smiled back, "There's a lot of different types of deciduous trees. These ones around here are mostly hardwood. Birch, Maple, Oak, Beech, Poplar, Ash." he said, pointing them out as they walked past, moving deeper into the small forest that surrounded Undyne's property.

Sans looked each tree over in turn, noting the difference between each, in color, and coarseness of the bark, and shape of the leaves. Papyrus stopped and set the small skeleton down allowing him to walk around and collect several of the fallen leaves. He ended up with a small bouquet, much to Sans delight, and Papyrus' tender amusement.

The two walked side by side, chatting about the different types of trees. Papyrus explained about how people would tap the trees for their sap in order to make syrup.

Several times various small animals darted out of the brush, startling them. Each time Sans would try to greet the small creatures. Only for them to bound away before he could get the first word out.

Sans had become increasingly sullen. Papyrus, who at first had been amused by the tiny skeleton's antics, became increasingly concerned instead.

A Robin fluttered down onto the branch of a nearby tree, and again Sans called out a soft greetings to it. The bird twittered back nonsensically, and Sans scowled openly at it.

"the animals around here are very rude." The tiny skeleton pouted, finally giving up, and allowing Papyrus to pick him up and cuddle him once again.

"If it makes you feel any better, they've never been known to answer anyone else either." Papyrus smiled sympathetically.

Sans stilled in his arms. Brow-bones furrowed.

"the animals here don't speak?"

"Not that I've ever seen. There are some types of birds, and dogs, and hell even cats, who can learn to mimic the sound of human words. But all that is is mimicry.. Animals don't talk." Papyrus answered.

Sans put his head down, staring at the bouquet of leaves in his tiny hands. A cloud of cyan dust coloring his cheeks.

"So the animals talk where you are from?" Papyrus asked carefully, trying to fix the awkwardness that had suddenly sprung up between them.

Sans looked miserable, his blush getting brighter, "yes... though now that i think about it, the ones in the underground are probably all just lesser monsters, like the dogs..."

He buried his face back in the red scarf, and Papyrus once again rubbed Sans small back to try and soothe the tiny monster.

Papyrus found two white Birch trees growing right beside one another, the second tree's trunk being bent over in the perfect angle to make a seat. He made his way one handedly up onto the tree, reclining back against the first tree, he shifted Sans from his arms into his lap and the two sat there, just enjoying the serenity of the forest around them.

"When I was eight," Papyrus began conspiratorially, "I decided that I wanted to live in a tree."

Sans looked up at him, eye sockets impossibly wide, opalescent eye-lights shining with delight.

"I had always had a great love of climbing. I never met a tree that I didn't try to scale." Papyrus continued, "And then, when I was eight years old, my class watched a movie. It was called The New Adventures of the Swiss Family Robinson. In the movie, a family of five survive a shipwreck, and end up stranded on an uncharted tropical island. And in order to survive, they build the single most epic tree house ever. I saw that movie, and instantly I wanted to live in a tree. I wanted to find the biggest tree I could, and I wanted to build a giant tree house and live in it, swinging from place to place on vines, just like in the movie."

Sans beamed up at him, and emboldened, Papyrus continued his story.

"Now, obviously from the start there was several problems with my plan. I was hardly about to find a forest full of massive, vine-ridden trees upon which to build my tree house. And even if I had somehow been able to, the fact was that I was an admittedly tall for my age, but scrawny eight year old. Not a full grown man with a whole family to help me build it. I didn't have any friends at that point either. At eight I was known as the weirdo who went around yelling all the time. Not exactly the best first impression..." Papyrus sighed sadly.

Sans looked up at him in distress, the corners of his permanent smile tight. Papyrus smiled gently and petted the tiny skeleton's back.

"So things were not working in my favor. But I was nothing if not determined. And I spent the whole following Summer scouring the woods around my town for the perfect tree. And finally, around the end of August, just before the next school year was about to begin, I found it. It was a magnificent old oak tree. It went straight up ten feet and then split, the branches spread out like a hand clawing at the sky. It was love at first sight. I climbed up and sat there, looking around, giggling, and bouncing with delight. The tree it turned out, wasn't actually all that far from my school you see. And so I decided that I would visit every day after school, and work on the tree house. And so for the next several weeks I did just that. Scrounging up every bit of wood I could find and drag there, from boards to tree branches, I slowly started to build my tree house." Papyrus explained wistfully, "I had only just gotten the first wall built when I was discovered. They were three older boys from the middle school... and they took one look at my poor tree house, and then decided that they didn't like it. And the next thing I knew, rocks were banging off the side of the wall, and I ducked one that ricocheted off the wall, only to move right into the path of a miss shot. The next thing I remember is coming to several hours later, laying face down on the ground with a massive headache, and a burning pain in one arm. I pulled myself up and stumbled home somehow, in the dark. And when my parents saw me they drove me straight to the hospital, and I ended up in bed for three weeks with a concussion, and a broken wrist. I had never been so restless in my entire life, and I am ashamed to admit that I drove my poor mother halfway insane with my constant fussing. Luckily for everyone I was asleep more than I was awake those first two weeks, but by the time that third week was up, my mother nearly disowned me. I still was forbidden to leave the house, but at least I could move around and play. Though I was still restless. Three days after I was finally let off bed rest, they allowed me to go back to school, and after school, before my father arrived to pick me up, I ran out into the woods to the oak tree..."

Sans sat staring up at him worriedly, as Papyrus sighed sadly again.

"My poor poor tree house was gone, all my hard work destroyed... they'd come back at some point and knocked down the wall I had built, and then... they broke each, and every last piece of wood I had managed to collect, into little, tiny pieces... Everything was ruined..."

Sans looked shocked, and outraged on his behalf. But Papyrus just smiled.

"I don't know how long that I sat there crying. But that's where my father found me. He had come to pick me up, only to find me missing, but a classmate of mine had seen me enter the woods, and pointed him in the right direction. And it was there that the full story finally came out. My parents had of course asked me what had happened several times prior to then. But I had lied and said that I fell while climbing, not wanting to get anyone in trouble... but I was so hurt, and angry to think that they had been so spiteful as to come back and do all that, just to make sure that I couldn't finish my tree house, that I just confessed the whole thing to my dad... This story does have a happy ending. I promise." Papyrus smiled gently, noting the tiny skeleton's increasingly distressed look.

"So to make a long story short, the bullies were finally brought to justice, and the following Summer my parents sent me away to camp- er, Summer Camps are places children go during the summer, to spend time outdoors. Hiking, swimming, climbing, horseback riding, you name it. I had never been to camp before, so I had a lot of fun... luckily by that time I was ten, and had learned the sacred art of volume control. So I wasn't ostracized for the entire Summer. I actually ended up making a few friends, none of which sadly lived anywhere near my town." Papyrus explained.

"But the best part of that Summer came when I was finally home, and and my parents lead me straight through to the back yard.." Papyrus Paused a wide smile stretching across his face, and Sans looked happier as well, sitting up straitened in anticipation of the next part of the story.

"There, right in my own backyard, perched between the branches of two large Maple trees, was the most amazing tree house I had ever seen... well, it wasn't as big as the one from the movie of course, but it had a rope ladder and hidden storage spaces to hide treasure in, a bookshelf and bunk beds and even a tire swing below. But the best part... the best best part, was the telescope out on the deck for looking at the stars.... I loved it. My father had worked all summer long on it while I was away at camp. Getting help from neighbors and friends, all of which came by the following week and had an end of summer party with us. And I spent every second I could out in that tree house. Though my mother outright banned me sleeping out the when it was cold. She was always too leery of fires to allow my father to install a heater you see... I kept that tree house in tiptop shape. True Undyne and I broke the bunks, and one of the railings,... and a couple of floor boards from jumping up and down so much... But I always made sure to fix whatever broke, and I used that tree house right up until the day I moved away for college... there were changes over the years of course... the children's books were swapped out for science books, the broken bunk beds were taken out, and replaced with a table and chairs, and cupboards were made for holding snacks... the only thing that didn't really change was the telescope. I made sure to take excellent care of that. It was my prized possession. And it's the only thing aside from a few books that I took with me when I finally moved out of my parents house and came here..." Papyrus said finally ending the story. He looked down to see an adoring smile on Sans face.

Papyrus blushed, and Sans realizing what he was doing, flushed cyan, the entirety of he's small skull turning blue as he once again hid his face.

Papyrus fidgeted, struggling with himself, jokes weren't his strong suit after all, "Funny, I thought that it was a good story. No need to be so blue..?"

He winced, and fully expected Sans to ignore him. Instead the tiny skeleton started trembling, (much to Papyrus' great concern.) And then started giggling.

Papyrus beamed, ridiculously proud of himself for the atrocious joke.

Sans and Papyrus had shared a companionable silence afterward, just sitting there listening to the leaves rustling overhead. Sans sorting his Leafy bouquet from largest to smallest.

Finally the tiny skeleton's hands stilled and he spoke.

"my bro never dreamed of living in a tree. we didn't have any good climbing trees in the underground. he did go through a frankly terrifying stage where he would climb up as high as he could, be it on furniture or rooftops, and then scream "catch me sans!!" at the top of his lungs and throw himself off."

Papyrus sucked in a breath and chuckled nervously, looking sheepish, "Yeaaaah... mighta gone through a phase like that at one point..."

Sans arched a brow-bone knowingly, and Papyrus blushed darkly, squirming. Sans chuckled, which only made it worse.

"he eventually grew out of it, thankfully. then he just decided to go join the royal guard- something between a police officer and an army man in human terms.- which gave me even more to worry about." Sans murmured, clear affection filling his voice. Papyrus looked down at him sympathetically, seeing the tiny sad smile. He rubbed Sans' back and hummed a soft tune. Sans nestled in closer, and sighed contentedly.

The silence stretched between them again, comfortably, and Papyrus found himself growing drowsy as he sat, with Sans curled safely in his lap, watching the leaves swaying above...

**Notes for the Chapter:**

> * So I had forgotten Mercy already addressed Hearts in the original fic. But I left that bit in regardless. No one has flawless memories. It's believable they'd discuss it more than once.
> 
> This one was one I was most nervous putting up since I added a bit to Papyrus's backstory. But I figure this is just a fan work and its not trying to change or undermined anything canon to Mercy's work.
> 
> It was originally a lot longer, it got too dark tho, ridiculously so. Gaster kidnapping Sans so. which was pushing things waaaay too far. so I trashed it. I do intend to explore some Canon Divergence such as 
> 
> "PAPYRI VARIABLES" = What If Sans didn't go to Nexustale alone? where Papyrus ended up in Nexustale too. 
> 
> or
> 
> "NEXUSSWAP"= Papyrus wakes up in a weird world where his brother's working as a Scientist... oh and his brother is human. Cue panic attack. 
> 
> Or much less world breaking: "INTERVIEW WITH A SKELETON" = What if they had called Mettaton?
> 
> There maybe a 2nd part to this eventually tho, as I do like the two wandering in the woods together. 
> 
> Anywho, hope you enjoy.


End file.
